Method of producing air gas from inflammable liquids



1,628,135 y 1927' H. FOERSTERLING METHOD OF PRODUCING AIR GAS FROM INFLAMMABLE LIQUIDS Filed March 5. 1925 .9 INVENIOR,

, ATTORNEY.

PJATENT OFFICE.

HANS FOERSTEBLING, OF JAMESIB'URG, NEW JERSEY.

METHOD OF PRODUCING AIR GAS FROM INFLAMMABLE LIQUIDS.

Application filed March 5, 1925. Serial No. 18,069.

This invention relates to method of producing air gas from an inflammable liquid and utilizing the same.

In my copending application Serial No. 13,068 filed March 1925, I have described a method of and an apparatus for making air gas from an inflammable liquid such as gasoline.

The invention of this application is a modification of the profess and its application of the aforesaid co-pending application as far as concerns its use as a heating medium.

I have found that if I use lcss than approximately 0.8 gal. of gasoline in vapor form per 1.000 cubic feet. of air the green inner core of the flame disappears qu ckly and the latter assumes a pale blue color. indicating a slight excess of oxygen over that required by theory for the complete combustion to carbon dioxide and water. If I decrease the flow of gasoline still further, leaving the flow of air the same. the gas so produced will not burn at all, inditating that the lower explosion limit has been passed.

Hence the pale blue flame is a sign that. the explosion limit is nearly reached. Such a flame is easily extinguished bv the least draft of air, as for instance when caused by an open window and may not be considered for any practical use under ordinary conditions.

Such a gas has however just the right composition for effecting heterogeneous surface combustion which requires only a very slight excess of oxygen over that required theoretically for the complete combustion of the combustible constituents to carbon dioxide and water.

While surface combustion is used to some extent in the industries for heating larger objects like boilers. furnaces. and the like, it has not yet found a foothold in household uses. Th s undoubtedly is due to the fact that all the fuel gas which is used for dome ti" purpoies requires an additional supply of air and such close regulation of air and gas as is necessary to obtain satisfactory results. cannot be expected from the average'user of the cooking stove.

\Vith mv method of making an air gas from an inflammable volatile liquid it is however easy to produce a gas which has the ideal composition for carrying out heterogeneous surface combustion. by simply regulatingthe proportion of air to the inmy invention all adjustment of valves for producing the correct mixture of air and gas is done away with, and the operation of this efficient method of heating is reduced to the simple process of opening a gas valve, lighting the flame and shutting the valve when the heat is no longer required.

Further features and objects of my invention will be more fully understood from the following detail description and the accompanying drawings, in which- Fig. 1 is a view, largely in vertical section and partly in side elevation, of one form of my invention;

Fig. 2, is a perspective view of one form of my heating burner; and

Fig. 3 is a section on line 3-3 of Fig. 2.

Referring to Fig. 1, 1 represents a fan or blower as is commonly used in the manufacture of air gas; the fan or blower 1 is provided at its back with an air intake (not .ll()\\'ll) and at its front with an axle conuected by suitable means such as the winch 2 actuated by the counterweight 3 by means of the wire rope 2 wound on the Winch 2. On the shaft 1 of the internal wheel of the fan or blower, I mount sprocket wheel 4 which drives by means of a chain'4 the sprocket wheel 5 keyed to or otherwise fixed on one end of the countershaft 6. At the other end'of the countershaft 6 is secured the eccentric or cam 7. The hub of the eccentric 7 is regulated by any suitable means, thereby controlling the proportion of the air to the liquid to be vaporized, as appears more fully hereinafter. The eccentric 7 drives by means of the lever 11, the rock shaft 12 and lever 11 the piston of the pump 14. 15 represents a storage tank for the inflammable liquid, located preferablv underground. The tank 15 is provided with a breather pipe 16 which serves at the same time as its filling means upon unscrewing the bend 17. The tank 15 is connected with the pump 14 by means of pipe line 18 provided at its end within the tank 15 with the foot valve 19.

The overflow 20 of pump 14, see Fig. 1, is conne-ted with the coil 21. The lower end of coil 21 is connected by means of the air line 25 with the outlet of fan or blower 1. By means of the pipe line 26 the bottom of the coil 21 is connected with overflow tank 27. The tank 27 collects the unvaporized residue of the gasoline as described more particuflammable volatile liquid accordingly. By larly hereinafter, and is emptied as required by unscrewing the bend 28 from its breather pipe 29, to permit a pump to be inserted through the pipe 29 and into the tank. The pipe line 26 is sealed within the tank 27 against the flow of the gas by means of its seal 30. The gas main 31 is connected to the up er end of the coil 21 as shown and is provlded witha test burner 32.

The cock 33 controls the air line 25 leading to the coil 21. The cock 34 controls the main gas line 31 and the cock 35 controls the test burner 32.

I now describe one method of carrying out my invention, but in doing so it must be understood that the same serves merely as an example of illustrating my process and the formation of my air gas.

The fan 1 is filled with a suitable sealing fluid, to the desired height. The storage tank 15 is filled with standard motor gasoline and enough gasoline is initially poured into storage tank 27 to cover seal 30. The cocks 33, 34 and 35 are now closed. The counterweight 3 is then wound up manually or otherwise. The cock 35 of the test-burner 32 is now opened. The fan 1 is set into motion and at the same time the gasoline pump 14 through the gearing including the sprocket wheels 4, '5, pumps gasoline from the tank 15 into the coil 21.

Upon regulating the pump 14 so that approximately 0.65 gal. of regular motor gasoline of the specific gravity of 0.746 or aproximately 57 B., per one thousand cubic eet of air are vaporized in the coil 21, the derived gas is of uniform quality and burns with a pale blue flame, thus indicating that there is a slight excess of oxygen over that required theoreticall for the complete combustion of the com ustible constituents to carbon dioxide and water and is of a compo sition suitable for heterogeneous combustion without any further addition of a combustion supporting gas.

In Fig. 2 of thls application I show a very simple construction of such a burner which can be used for a cooking stove in connection with heterogeneous surface combustion. 40 represents a cast iron shell to which is attached the gas piping 41 with a gas cock 42, while 43 is a piece of strong mesh of fine wire, 44 is a sheet iron mantle extending somewhat above the casting 40 for conducting the heat away from the cast iron. and 45 is a layer of loose, small pieces of ordinary fire brick as for instance passing through (an 8 mesh sieve and being retained by a 13 mesh sieve somewhat exaggerated in the drawings.

With a burner of 2.5" diameter:4.9 sq. in. and a layer of granularmaterial 1 high, with a gas ressure of approximately 1". I have asse the mixed gas through at the rate 0 17.5 cubic feet er hour or 3.6 cubic feet of mixed gas per our and per square inch of burner surface.

The burner for the heterogeneous combustion, such as the burner 39 as shown in Figs. 2 and 3, has its piping 41 devoid of any secondary air supply, that is to say, the air gas is led direct throu h the main gas line 31 to the iping 41 0 each burner 39 without any ad itional supply of oxygen.

In order to find out what the efliciency of such a burner is in comparison with the burner described in my aforesaid co-pendin application the following tests were carried out. D

In each case 2.2 pounds of water was heated from 15 to 90 C. An aluminum pot measuring 7" in diameter by 5" high and provided with a cover was used. The temperature was taken at regular intervals. Instead of using a pump for passing the gasoline through the vaporizer and catching the unvaporized gasoline in a tank, standard grade of motor asoline of approximately 56 B. was fed rom a graduated cylinder provided with a glass regulating cock and the recovered gasoline was caught in a regular measuring cylinder. The feeding was regulated by hand so that an approximately uniformly slow flow was obtained. The results were as follows 1. Homogeneous flame combustion:

To heat 2.2 pounds of water from 15 to 90 C. there were required 12.16 fluid drams of gasoline and recovered 7.58 fluid drams of gasoline. Hence the used and vaporized gasoline:4.58 fluid drams of gasoline or 37.7% of vaporization. Assuming that 1 gal. of gasoline:124,000 B. t. u. the 4.58 fluid drams correspond to 554 B. t. 11.

To heat 2.2 pounds of water 75 C. there is required theoretically 297 B. t. 11. Hence an efliciency of 53% was obtained. Other data taken: the time of heating was 18 minutes. The amount of air used was 5.25 cubic feet. The distance from the burner plate to the bottom of the pot was A", the gas pressure was about 1" the A" brass with a A, ore, and wide open.

2. Heterogeneous surface combustion:

To heat 2.2 pounds of water 75 C. there were required 9.48 fluid drams of gasoline and recovered 4.87 fluid drams of gasoline. Hence the used and vaporized gasoline: 4.61 fluid drams of gasoline:48.6% vaporization. As the same amount of gasoline was used as with homogeneous combustion the efficiency remains the same or equals 53%. The time of heating was 21 minutes, the amount of air used 6.72 cubic feet; the distance from the burner to the bottom of the pot-was All other of the aforesaid data remained the same.

The results of the hereinabove test 2, as compared with the hcreinabove test 1, show that from a given quantity of gasoline, a greater percentage of the volatile constituents of the gasoline are vaporized pursuant to as cock used was of a my invention by making an air gas suitable for heterogeneous combustion instead of an air gas suitable for homogeneous combustion, or expressing it differently, by producing a gas suitable for heterogeneous combustion approximately 45% of the total B. t. 11. contained in a given amount of gasoline can be extracted and converted into air gas against only approximately when an air gas is producedsuitable for homogeneous combustion. The approximate figures are 45% vaporization against35% with a corresponding actual consumption of approximately 0.65 gal. of gasoline as against 0.8 to 0.93 gal. per 1000 cubic feet of air.

As additional advantages of a combination of air gas in connection with surface combustion I like to mention the following:

It allows bringing the surface of the burner and the object to be heated close together. The distance between the burner and the bottom of the object to be heated in a regular gas stove is about 15 Such a distance is, of course, a source of great heat losses and particularly whenever a draft is created in proximity of the flame. It is obvious that the overall efliciency under actual working conditions as they exist in akitchen throughout the year is in favor of a burner which can be set as closely as possible to the object to be heated. The electrically heated pot proves this where the means of heating and the object to be heated form one unit.

'ith homogeneous flame combustion it happens sometimes that the flame flashes back, when a sudden draft is created. as when a. window or door is opened. Some- 0 times a gust of wind will even blow out the flame and if nobody is present unburnt gas may escape.

\Vith surface combustion this is impossible: even the strongest wind can not extinguish the burner.

It is obvious that the amount of 0.65 galof gasoline vaporized per 1000 cubic feet of air is only up roximate and may vary slightly with di erent types of gasoline; it may also depend somewhat on the construction of the burner used, as some burners will allow a regulation closer to the theoretically required quantities of fuel and air for complete combustion than others, but the exact regulation will not be difficult for those skilled in the art. The exact quantities of gasoline and air are those which produce a flame. which under homogeneous combustion conditions will show a blue color and which is easily extinguished by a slight draft of air. An air gas whichshows atthe test burner these characteristics will give a flameless incandescent surface when a heterogeneous surface combustion burner is used.

It is obvious that when I say I can vaporize approximately 45% of gasoline and produce a gas suitable for heterogeneous surface combustion in comparison to approximately 35% with homogeneous flame combustion, such figures are only relative. They depend firstly, on the air temperature which governs the vapor tension and secondly, on the prodnot the same as it was ten years ago and as itmight be ten years from now. Further, that the composition varies with different countries. Initial boiling points, final boiling points, percentages of fractional distillation to a certain temperature, and the proportion which can be vaporized with a given amount of air are not fixed factors. Hence, in order to obtain the best results with a given quality of gasoline it becomes necessary to determine the proper proportion of air to gasoline, which however is a very simple thing with the apparatus I have described in my aforesaid co-pending application. Upon determining the proportion of air to gasoline or other volatile inflammable liquid. such proportion is maintained independently of the rate of consumption of the gas.

The standard grade of motor gasoline referred to in the specification comprises a complex volatile inflammable liquid composed of various organic compounds. It does not possess a definite boiling point, boiling between wide ranges of temperatures. It also does not possess a definite vapor tension, some of its constituents forming at normal temperature with air an ignit-ible gas, others giving a mixture too lean to burn. Hence motor gasoline might be .termed a liquid possessing partly sufficient vapor tension to form with air an ignitable gas in cont-radistinction to, for instance, ben zol. which forms at normal temperature with air an ignitable gas because it possesses wholly sufli'cient vapor tension.

It must be clearly understood that I do not wish to be limited to any particular grade of gasoline and that I can use for my purpose other complex volatile inflammable liquids in accordance with the method described, provided that these liquids contain compounds which will give with air an ig-' nitable gas.

Other such complex compounds are. for instance. the various grades of crude oil,

from which the gasoline has not been extracted. It will be obvious that using a gasoline containing crude oil according to my method the percentage of the recovered portion of the liquid is increased but otherwise the production of the air gas suitable for heterogeneous combustion is not interfered with.

Instead of a crude petroleum oil, I can us( also a crude benzol which constitutes lit) likewise a complex volatile inflammable liqtially not larger than are required within md possessing partiali sufiicient vapor tell-f a given time period, regulating the quantity sion to form an ignitab e gas with air at normal temperature.

\Vhile such complex volatile inflammable liquids usually have the inherent advantage of being inexpensive, it must further be obvious that my invention is not limited to such liquids and may be carried out by the use of liquids possessing wholly sutlicient vapor tension to form at normal temperatures with air an ignitable gas, such as benzol, acetone. special grades of low boiling gasoline and alcohols in mixture with other suitable compounds.

Vhereas, I have described my invention by reference to specific forms thereof, it will be understood that many changes and modifications may be made without departing from the spirit of the invention.

1. The method of producing an air gas of a substantially uniform heating value, which comprises vaporizing a moving thin stream of a volatile inflammable liquid at atmospheric temperatures in counter-direction to a current of air of low pressure and in quantities substantially not larger than are required within a given time period, regulating the quantity of the liquid independently of the current of air to obtain an air gas the oxygen content of which is slightly above the amount theoretically required for the complete combustion of its combustible constituents, maintaining such regulation of the composition of the air gas independently of the rate of consumption of the air gas, and recovering the unvaporized portion of the liquid.

2. The method of producing an air gas of a substantially uniform heating value, which comprises vaporizing a moving stream of a volatile inflammable liquid at atmospheric temperatures in counter-direction to a currentof air of low pressure and in quantities substantially not. larger than are required within a given time period, regulating the quantity of theJiquid independently of the current of air to obtain an air gas the oxygen content of which is slightly above the amount theoretically required for the complete combustion of its combustible constituents, maintaining such regulation of the composition of the air independently of the rate of consumption of the air gas, maintaining the temperature of the liquid while being thus vaporized at substantially the temperature of the atmosphere. and recoving the unvaporized portion of the liquid.

3. The method of producing an air gas of a substantially uniform heating value. which comprises vaporizing a moving thin stream of gasoline at atmospheric temperatures in counterdirection to a current of air of low pressure and in quantities substanof the gasoline independently of the current of air to obtain an air gas the oxygen contcnt of which is slightly above the amount theoretically required for the complete combustion of its combustible constituents, maintaining such regulation of the composition of the air gas independently of the rate of consumption of the air gas, and recovering the unvaporized portion of the gasoline.

4. The method of producing an air gas of a substantially uniform heating value, which comprises, vaporizing a moving thin stream of gasoline at atmospheric temperatures in counterdirection to a current of air of low pressure and in quantities substan: tially not larger than are required within a giventime period, regulating the quantity of the gasoline independently of the current of air to obtain an air gas the oxygen content of which is slightly above the amount theoretically required for the complete comlmstion of its combustible constituents, maintaining such regulating of the composition of the air gas independently of the rate of consumption of the air gas, maintaining the temperature of the gasoline while being thus vaporized at substantially the temperature of the atmosphere, and recovering the unvaporized portion of the gasoline.

The method of producing an air gas of a substantially uniform heating value, which comprises conveying from a place of storage a complex volatile inflammable liquid possessing partly sufficient vapor tension to form with air at atmospheric temperatures and low pressure an ignitable air gas. vaporizing the liquid at atmospheric temperatures in the form of a thin moving stream in counter-direction to the current of air of low pressure and in quantities substantially not larger than are required within a given time period, regulating the quantity ot the liquid independently of the current of air to obtain an air gas the oxygen content of which is suitable for heterogencous combustion without further addition of air to the air gas so produced, maintaining such regulation independently of the rate of consumption of the air gas, maintaining the temperature of the liquid while being thus vaporized at substantially the temperature of the atmosphere, recovering the unvaporized portion of the liquid possessing insufiicient vapor tension to be vaporized. and conveying the produced air gas to the location of consumption at atmospheric temperatures.

6. The method of converting a volatile inflammable liquid into an air gas suitable for heterogeneous combustion without further addition of air, comprising vaporizing the liquid with air in such a proportion that an air gas is directly obtained, the oxygen content of which is slightly above that required theoretically for the complete combustion of the combustible constituents and which ceases to burn upon further dilution with air.

7. The method of converting a volatile inflammable liquid into an air gas suitable for heterogeneous combustion without further addition of air, comprising vaporizing 10 the liquid at substantially atmospheric temperatures with air in such a proportion that an air gas is directly obtained, the oxygen content being slightly above that required theoretically for the complete combustion of the combustible constituents and which ceases to burn upon further dilution with air.

in testimony whereof I have signed this specification this 28th da of February, 1925.

HANS F ERSTERLING. 

